A driver for a Thin Film Transistor Liquid Crystal Display (TFT-LCD) mainly comprises a gate driver and a data driver, wherein the gate driver converts an inputted clock signal via a shift register unit and then applies the same to a gate line on a liquid crystal display (LCD) panel; and a gate driving circuit of the gate driver can be formed on the LCD panel together with TFTs at the same time under a same process. The gate driving circuit comprises a plurality of stages of shift register units, and each stage of shift register unit is connected to a corresponding gate line to output a gate driving signal.
The gate driving circuit with the above structure is arranged on the LCD panel, and each stage of shift register unit comprises a structure as shown in FIG. 1. The shift register unit shown in FIG. 1 comprises a storage capacitor C1 and a TFT M3 configured to supply a first clock signal CLK to an output terminal OUTPUT in response to a voltage at a pull-up node PU. Here, the storage capacitor C1 mainly functions as supplying a relative stable voltage to the pull-up node PU so that it is ensured that a stable signal is outputted. The TFT M3 has a large size, that is, it has a thick depletion layer; and the thick depletion layer can reduce an influence of the couple capacitance in the TFT, and can further improve the stability of the output signal and maintain the voltage at the output terminal. At the same time, the shift register unit shown in FIG. 1 further comprises six signals (INPUT, CLK, CLKB, VDD, VSS and VGL) functioning as control signals for achieving the output and reset functions of the shift register unit.
However, the introduction of the storage capacitor C1, the increase of the size of the TFT M3 and more control signals lead to a larger wiring space, so that the shift register unit as a whole is larger in size and thus the liquid crystal display is larger in volume.